Male breast cancer is a disease in which malignant (cancer) cells form in the tissues of the breast.

Breast cancer may occur in men. Men at any age may develop breast cancer, but it is usually detected (found) in men between 60 and 70 years of age. Male breast cancer makes up less than 1% of all cases of breast cancer.

Radiation exposure, high levels of estrogen, and a family history of breast cancer can increase a man’s risk of breast cancer.

Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. Talk with your doctor if you think you may be at risk. Risk factors for breast cancer in men may include the following:

The genes in cells carry the hereditary information that is received from a person’s parents. Hereditary breast cancer makes up about 5% to 10% of all breast cancer. Some mutated genes related to breast cancer are more common in certain ethnic groups. Men who have a mutated gene related to breast cancer have an increased risk of this disease.

There are tests that can detect (find) mutated genes. These genetic tests are sometimes done for members of families with a high risk of cancer. See the following PDQ summaries for more information:

Men with breast cancer usually have lumps that can be felt.

Lumps and other signs may be caused by male breast cancer or by other conditions. Check with your doctor if you notice a change in your breasts.

Tests that examine the breasts are used to detect (find) and diagnose breast cancer in men.

The following tests and procedures may be used:

Physical exam and history : An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.

Clinical breast exam (CBE): An exam of the breast by a doctor or other health professional. The doctor will carefully feel the breasts and under the arms for lumps or anything else that seems unusual.

Ultrasound exam: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. The picture can be printed to be looked at later.

MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).

Blood chemistry studies : A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it.

Biopsy : The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer. The following are different types of biopsies:

HER2 test: A test to measure the amount of HER2 in cancer tissue. HER2 is a growth factorprotein that sends growth signals to cells. When cancer forms, the cells may make too much of the protein, causing more cancer cells to grow. If cancer is found in the breast, tissue from the tumor is checked in the laboratory to find out if there is too much HER2 in the cells. The test results show whether monoclonal antibodytherapy may stop the cancer from growing.

Survival for men with breast cancer is similar to survival for women with breast cancer.

Survival for men with breast cancer is similar to that for women with breast cancer when their stage at diagnosis is the same. Breast cancer in men, however, is often diagnosed at a later stage. Cancer found at a later stage may be less likely to be cured.